JP3980323B2 - Surface acoustic wave duplexer - Google Patents
Surface acoustic wave duplexer Download PDFInfo
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- JP3980323B2 JP3980323B2 JP2001328692A JP2001328692A JP3980323B2 JP 3980323 B2 JP3980323 B2 JP 3980323B2 JP 2001328692 A JP2001328692 A JP 2001328692A JP 2001328692 A JP2001328692 A JP 2001328692A JP 3980323 B2 JP3980323 B2 JP 3980323B2
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- 238000010897 surface acoustic wave method Methods 0.000 title claims description 80
- 238000010586 diagram Methods 0.000 description 18
- 230000005540 biological transmission Effects 0.000 description 12
- 239000003990 capacitor Substances 0.000 description 12
- 238000010295 mobile communication Methods 0.000 description 9
- 230000006378 damage Effects 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 6
- 230000001413 cellular effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- IRLPACMLTUPBCL-KQYNXXCUSA-N 5'-adenylyl sulfate Chemical compound C1=NC=2C(N)=NC=NC=2N1[C@@H]1O[C@H](COP(O)(=O)OS(O)(=O)=O)[C@@H](O)[C@H]1O IRLPACMLTUPBCL-KQYNXXCUSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
- H03H9/6423—Means for obtaining a particular transfer characteristic
- H03H9/6433—Coupled resonator filters
- H03H9/6483—Ladder SAW filters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/60—Deposition of organic layers from vapour phase
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
- C23C16/45502—Flow conditions in reaction chamber
- C23C16/45504—Laminar flow
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
- C23C16/45587—Mechanical means for changing the gas flow
- C23C16/45591—Fixed means, e.g. wings, baffles
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/48—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating by irradiation, e.g. photolysis, radiolysis, particle radiation
- C23C16/482—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating by irradiation, e.g. photolysis, radiolysis, particle radiation using incoherent light, UV to IR, e.g. lamps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
- B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
Description
【0001】
【発明の属する技術分野】
本発明は、携帯電話機等の小型移動体通信器において、弾性表面波共振器による梯子型構成の帯域通過形フィルタを備えた弾性表面波分波器に関し、特に、印加電力の高い場合にも使用可能な弾性表面波分波器に関する。
【0002】
【従来技術】
近年、小型で、軽量な携帯電話機等の移動体通信機器端末の開発が急激に進められている。これに伴い、用いられる部品の小型化、高性能化が追求されている。この傾向に対応するべく弾性表面波(以下、「SAW」という)フィルタを用いたRF(ラジオ周波数)部品が開発され、用いられている。特に、図9のSAW分波器はRF部の小型化に大きく貢献するデバイスのため、活発に開発が行われ、一部、実用化され、用いられている。
【0003】
図9はSAW分波器の基本構成図である。この図では、アンテナが接続されるANT(アンテナ)端(100)を中心として、Tx端(送信端)(101)との間にTxフィルタ(送信用フィルタ)(200)が接続され、Rx端(受信端)(102)との間には分波線路(400)とRxフィルタ(受信用フィルタ)(300)が接続されている。
【0004】
これらSAWデバイスとして、近年、移動体通信機器端末の性能向上のため、通過帯域の更なる低挿入損失化及び減衰帯城の高減衰量化された高性能SAW分波器が要望されている。このSAW分波器は、移動体通信機器端末における信号の分岐、生成を行うために送信信号と受信信号が干渉しないように、図9に示す如く、Txフィルタ(200)、Rxフィルタ(300)および分波線路(400)から構成されている。
【0005】
ここで用いられる各フィルタおよび分波線路は一般的な特性のCDMA(Code Division Multiple Access)方式のものを用いた。以下、図1を除く他の各図に示される回路素子等は同様に一般的な特性のものを対象としている。また、各表のデータは本発明に係るデータ以外は一般的な特性のものに基づくデータである。表の本発明に係るデータおよび図1の回路素子等は本発明に係るAMPS/CDMA方式のものである。
【0006】
図6は実装状態を示すSAW分波器の回路構成図である。
【0007】
このSAW分波器は、ANT端(100)においてアンテナ(170)に、Tx端(101)において高電力を出力する送信電力増幅器(180)におよびRx端(102)において受信した小信号を増幅する低雑音増幅器(190)に接続されている。
【0008】
【発明が解決しようとする課題】
前記送信用フィルタ(200)は、高電力が印加されることとなるため、この高電力の印加によっても特性劣化のないSAWフィルタであることが必要となる。この高電力化SAWフィルタは、例えば特開平6−29779号公報、特開平10−303682号公報および特開平11−251871号公報に示されている。
【0009】
上記公報に用いられているフィルタは、図2に示すように、送信用フィルタを構成するSAW共振器の交差長、対数を増やして、単位電流当たりの面積を増やして高耐電力化したSAWフィルタが用いられている。
【0010】
図2はTxフィルタの回路構成図である。
【0011】
このTxフィルタ(200)は直列腕S1(210)、S2(211)およびS3(212)、並列腕P1(220)およびP2(221)、有極用L(230)からなる梯子型フィルタに構成されている。
【0012】
しかし、図2に示す高電力化したSAWフィルタを図9のSAW分波器に用いて、高電力を入力するようにした場合、分波器に特性劣化が生じることがわかってきた。そこでこの特性劣化についてみてみる。
【0013】
移動体通信機器端末においては、必然的にアンテナ部のインピーダンス変化は大きい。したがって、このアンテナ部(170)のインピーダンスの変化による移動体通信機器端末の性能劣化が問題になる。この問題点を技術的な要求に換言すると、分波器からみて、ANT端(100)、Rx端(102)を50Ω(オーム)で終端した場合と、ANT端(100)、Rx端(102)を開放した場合で特性上変化のない技術が求められることとなる。しかしながら、ANT端(100)、Rx端(102)を開放した場合、Txフィルタ(200)の特性劣化もしくはその直列腕の破壊によって信号断の生じることが知られている。
【0014】
一方、携帯電話機等の移動体通信端末機器における図9及び図6のSAW分波器は1本のアンテナを送信用および受信用に用いる機能と共に次の機能も求められている。
【0015】
(1)アンテナが通常に動作した場合、即ち、アンテナの人力インピーダンスが50Ωの場合、
(2)アンテナが解放の場合、即ち、アンテナの入力インピーダンスが無限大の場合、
の各場合において、特性に変化がない機能が要求されている。
【0016】
上記、(1)及び(2)の場合、インピーダンスの急激な変化の状態のため、SAW分波器に電力が印加される送信時のSAW分波器特性の変動および破壊が問題となる。このSAW分波器特性の変動および破壊は主に高電力が印加される送信用フィルタの直列腕共振器の劣化及び破壊に起因するものであることが知られている。
【0017】
本発明は、上記の問題に鑑み、直列腕に流れる電流を少なくして、直列腕の印加電力を低くし、弾性表面波フィルタの直列腕共振器の劣化および破壊を抑制することを目的とする。
【0018】
【課題を解決するための手段】
本発明は、上記目的を達成するために以下の手段を採用する。
(1)第1の直列腕弾性表面波共振器と、第2の直列腕弾性表面波共振器と、前記第1の直列腕弾性表面波共振器と前記第2の直列腕弾性表面波共振器との間に接続される第3の直列腕弾性表面波共振器とを含み、それぞれが直列に接続される複数の直列腕弾性表面波共振器、及び前記第1の直列腕弾性表面波共振器に並列に接続される第1の並列腕弾性表面波共振器と、前記第3の直列腕弾性表面波共振器に並列に接続される第2の並列腕弾性表面波共振器とを含む複数の並列腕弾性表面波共振器を備えた弾性表面波分波器であって、前記第3の直列腕弾性表面波共振器の共振周波数を、前記第1の直列腕弾性表面波共振器の共振周波数及び前記第2の直列腕弾性表面波共振器の共振周波数とは異ならせたことを特徴とする。
(2)第1の直列腕弾性表面波共振器と、第2の直列腕弾性表面波共振器と、前記第1の直列腕弾性表面波共振器と前記第2の直列腕弾性表面波共振器との間に接続される第3の直列腕弾性表面波共振器とを含み、それぞれが直列に接続される複数の直列腕弾性表面波共振器及び前記第1の直列腕弾性表面波共振器に並列に接続される第1の並列腕弾性表面波共振器と、前記第3の直列腕弾性表面波共振器に並列に接続される第2の並列腕弾性表面波共振器とを含む複数の並列腕弾性表面波共振器を備えた弾性表面波分波器であって、対数若しくは交差長を異ならせることによって、前記第3の直列腕弾性表面波共振器に印加される電力を、前記第1の直列腕弾性表面波共振器に印加される電力及び前記第2の直列腕弾性表面波共振器に印加される電力とは異ならせたことを特徴とする。
(3)上記(1)記載の弾性表面波分波器において、前記第1の直列腕弾性表面波共振器の共振周波数と前記第2の直列腕弾性表面波共振器の共振周波数とは等しいことを特徴とする。
(4)上記(2)記載の弾性表面波分波器において、前記第1の直列腕弾性表面波共振器に印加される電力と前記第2の直列腕弾性表面波共振器に印加される電力とは等しいことを特徴とする。
【0019】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて詳細に説明する。
【0020】
(第1実施例)
図1は本発明の第1実施例のTxフィルタ(200)の回路構成図である。
【0021】
図6に示す、携帯電話機等の移動体通信の端末機器は、通常、電力増幅器(180)の出力端であるPA端(103)の出力インピーダンスZPoutが50Ωに規定されている。この電力増幅器(180)の出力電力はSAW分波器のTx端(101)において、Txの入力インピーダンスZTinと電力増幅器(180)の出力インピーダンスZPoutの関係から、SAW分波器のTx端(101)からTxフィルタ(200)に入力する電力とSAW分波器のTx端(101)から電力増幅器(180)のPA端(103)に反射する電力になることが知られている。
【0022】
携帯電話機等の移動体通信の端末機器において、図6のTxフィルタ(200)は、図1の3個の直列腕S1(210)、S2(211)およびS3(212)と2個の並列腕P1(220)およびP2(221)で構成された4段T型梯子型フィルタで、その交差長および対数を表1に示す。
【0023】
【表1】
図3は、Rxフィルタ(300)の回路構成図である。Rxフィルタ(300)は、図3に示す如く、3個の直列腕S1(310)、S2(311)およびS3(312)と4個の並列腕P1(320)、P2(321)、P3(322)およびP4(323)で構成された6段π型フィルタもあり、その交差長および対数を表2に示す。
【0024】
【表2】
図7は、Txフィルタ(200)の集中定数等価回路図である。
【0025】
図8は、Rxフィルタ(300)の集中定数等価回路図である。
【0026】
図7において、直列腕S1(210)およびS3(212)はリアクタンスLS1と容量CS1の直列回路に容量CS0を並列接続した単位回路を2個直列接続した回路となり、直列腕S2(211)はリアクタンスLS2と容量CS2の直列回路に容量CS1を並列接続した単位回路を2個直列接続した回路となり、並列腕P1およびP2はリアクタンスLP1と容量CP1の直列回路に容量CP0を並列接続した単位回路を2個直列接続した回路となる。
【0027】
図8において、直列腕S1(310)、S2(311)およびS3(312)はリアクタンスLS1と容量CS1の直列回路に容量CS0を並列接続した回路となり、並列腕P2、P3およびP4はリアクタンスLP1と容量CP1の直列回路に容量CP0を並列接続した回路となり、並列腕P1はリアクタンスLP1と容量CP1の直列回路に容量CP0を並列接続した単位回路を2個直列接続した回路となる。
【0028】
各直列腕および並列腕の等価LC値を表1に示す。本発明の第1実施例は図1の梯子型Txフィルタ(200)の構成に関し、図6のSAW分波器に於いて、送信電力入力時、図9のTxフィルタ(200)の各直列腕共振器に印加される電力を小さくすることを特徴とするものである。
【0029】
信号の送信時にTxフィルタ(200)に入力する電力に注目する必要がある。図6から、このTxフィルタ(200)の入力電力はTxフィルタ(200)の入力インピーダンスZTinに関係することがわかる。即ち、送信時には、負荷はANT端(100)に並列に分波線路(400)、Rxフィルタ(300)からなる受信系のインピーダンスZRLinが接続された状態になっている。
【0030】
ここで問題なのは、Txフィルタ(200)を構成する図7の各共振器(210、211、212、220、221)に印加される電力が高くなったときに、各共振器の有限のQにより生じる共振器の櫛歯間抵抗分に、電流が流れ、この電流により共振器内に熱が発生し、この熱により共振器が破壊されることである。但し、共振器「Q」は、
Q=2π(蓄積されたエネルギー)/(1サイクル中に消失するエネルギー)
=2πf(蓄積されたエネルギー)/(消失する電力)とする。
【0031】
図4は直列腕SAW共振器の回路構成図である。
【0032】
図5は直列腕SAW共振器の集中定数等価回路図である。
【0033】
図4は直列腕共振器S1(410)の概略図であり、図5は図4の直列腕共振器S1(510)の集中定数等価回路であり、容量Cs1とリアクタンスLs1の直列回路と容量Csoの直列回路を並列接続し、それらに抵抗Rs520を直列接続した回路となる。
【0034】
通常、図4の直列腕共振器S1(410)の有限のQによる抵抗分は図5の直列腕共振器S1(510)の集中定数回路から、抵抗分Rs(520)として評価され、算出される。図5の共振器の有限のQによる抵抗分Rs(520)は共振器の集中定数等価回路から次の様に求められる。いま、共振器のQを有限のQ0 とすると、Q0 を含む直列腕共振器のインピーダンスZ、並列腕共振器のアドミタンスYは式(1)で与えられる。
Z=1/Y=Rd +jZ0 =1/(Gd +jY0 ) (1)
Gd ={ωC0 +ωC1 (1+ω^2*L1 *C1 )}/{(1−ω^2*L1 *C1 )^2}/Q0 (2)
Y0 =ω(C0 +C1 +ω^2L1 *C1 *C0 )/(1+ω^2*L1 *C1 ) (3)
各共振器のQが無限大の場合は直列腕共振器のインピーダンスはjZ0 、並列腕共振器のアドミタンスはjY0 となる。しかし、各共振器は、実際は有限のQのため、直列腕共振器の微小の抵抗分Rd 、並列腕共振器の微小のコンダクタンス分Gd が存在する。
【0035】
表1のTxフィルタ(200)の各直列腕共振器の等価LC値から、Txフィルタ(200)の824(MHz)、836(MHz)および849(MHz)における抵抗値を、各共振器のQを800として、式(1)、式(2)および式(3)から求めた値を表3に示す。
【0036】
【表3】
Txフィルタ(200)に送信電力が印加された場合、図6に示す如く、等価電力と反射電力に分かれる。この等価電力は表3に示されるTxフィルタ(200)の高周波抵抗により熱に変わる。今、表3において、周波数836(MHz)に着目すると、直列腕2の抵抗値が3.77Ωで、直列腕1、3の1.93Ωの略2倍の抵抗を持つことがわかる。即ち、直列腕2が他直列腕に比較して、略2倍の熱を発生していることがわかる。この表3の高周波抵抗を基にして各直列腕に流れる電流を求め、各直列腕の印加電力を求めると、表4になる。
【0037】
【表4】
この表4から、直列腕2に最も高い電力が印加されることがわかる。即ち、直列腕2が電力に対して最も弱いことがわかる。このことは前述の如く高周波抵抗が大きいことに起因する。
【0038】
通常、Txフィルタ(200)の直列腕は等しい共振周波数に設定されている。しかし、直列腕2の印加電力を小さくするためには、表3によれば、周波数を変えると、各直列腕の高周波抵抗が変わることから、本発明の第1実施例は図9のTxフィルタ(200)の直列腕1及び直列腕3と直列腕2の共振周波数を異ならせることにより、Txフィルタ(200)の直列腕2の高周波抵抗を小さく設定し、印加電力を少なくすることにより、耐電力特性の向上したSAW分波器とすることができることになる。
【0039】
【表5】
本発明の第1実施例は、表5に示す如く、直列腕2(R3)の共振周波数を869(MHz)から高周波側に設定することにより、直列腕2(R3)の高周波抵抗を本実施例によれば869MHzで3.77Ωから885MHzで1.93Ωへ減少させるもので、結局直列腕2の印加電力を低くするものである。
【0040】
そこで、本発明の第1実施例における、直列腕2の共振周波数を変える手段としては、具体的には、櫛歯電極の電極間ピッチを変える手段が採用可能である。例えば、グレーティング反射器の場合、グレーティング周期(金属、誘電体ストリップの配置間隔)をp、表面波速度をv0 とすると、反射器の中心周波数f0 は、f0 =v0 /2pの式から求めることができる。即ち、表面波速度が一定の場合、グレーティング周期を変えることにより直列腕2の共振周波数を変えることができる。さらには、直列腕2の共振周波数の変化により周波数特性は変化するが、この周波数特性の変化は各直列腕の交差長および対数で補正可能である。
【0041】
表5には本発明の効果が実質的に示されている。通常、各直列腕は全て869(MHz)に設定されている。表5には直列腕2の共振周波数を(869〜885)(MHz)に変化させた場合の各直列腕の場合の抵抗及び印加電力が示されている。直列腕2の共振周波数を869(MHz)から885(MHz)に変化させることにより、直列腕2の印加電力は0.074(Watt)から0.019(Watt)に変化することがわかる。
【0042】
(第2実施例)
図2は、本発明のTxフィルタの回路構成図である。
【0043】
本発明の第2実施例の回路構成は図2に示す有極型構成である。
【0044】
前記第1実施例は最も印加電力の大きい直列腕2に注目して、直列腕2の共振周波数を変えて、直列腕2の抵抗を小さくして直列腕2の印加電力を低くした。
【0045】
それに対し、この第2実施例は、図2のTxフィルタ(200)の回路において、並列腕1、2の抵抗を小さくして、直列腕2に流れる電流を並列腕1に分流して、直列腕2の印加電力を低くしたことを特徴とする。並列腕の抵抗を小さくする手段としては、歯の交差長を長くして単位面積当たりの電流値を小さくする手段、対数を増加して同じく単位面積当たりの電流値を小さくする手段、等がある。
【0046】
表6に並列腕単体の抵抗値と多段型フィルタを組んだときの各直列腕と各並列腕の抵抗値を示す。表6のNO.1の例が第1実施例で基準とした構成である。
【0047】
【表6】
この並列腕1、2の抵抗値が15Ωの例は並列腕共振器のQが200の場合である。表6には、並列腕1、2の抵抗値が15Ωから10Ω、7.62Ωと変わるにつれて、直列腕2の抵抗値のみが3.74Ωから3.71Ω、3.66Ωと減少するデータが示されている。このデータから、並列腕の抵抗値を小さくするにつれて、直列腕2の抵抗値が同じく小さくなる原理が解る。
【0048】
表7に第2実施例の並列腕単体の抵抗値と多段型フィルタを組んだときの各直列腕および並列腕に印加される電力を示す。
【0049】
【表7】
表7のNO.1は前述の如く、第1実施例で基準とした構成で、直列腕2の印加電力が最も大きい。並列腕の抵抗値を15Ωから10Ω、7.62Ωと小さくすることにより、直列腕2の印加電力を0.076(Watt)から0.064(Watt)、0.056(Watt)と小さくできることがわかる。さらには、直列腕3の印加電力も、同様の傾向を示し0.031(Watt)から0.024(Watt)、0.020(Watt)と小さくできることがわかる。このデータから、並列腕の抵抗値を小さくするにつれて、直列腕2および3の印加電力が小さくなる原理が解る。
【0050】
以上のように、第2実施例の有極型Txフィルタ(200)の回路構成における各直列腕の印加電力を低くする手段は、第1実施例の構成では得られない高性能特性が得られ、第1実施例のものと同時に適用可能である。
【0051】
第2実施例では並列腕の高周波抵抗を小さくし、直列腕に流れる電流を少なくして、直列腕の印加電力を低くする手法を用いて、有極型Txフィルタ(200)の耐電力特性を向上した。
【0052】
【発明の効果】
本発明は、特許請求の範囲記載の事項により、直列腕に流れる電流を少なくして、直列腕の印加電力を低くし、弾性表面波フィルタの直列腕共振器の劣化および破壊を抑制することができる。
【図面の簡単な説明】
【図1】 本発明の第1実施例のTxフィルタの回路構成図である。
【図2】 Txフィルタの回路構成図である。
【図3】 Rxフィルタの回路構成図である。
【図4】 直列腕SAW共振器の回路構成図である。
【図5】 直列腕SAW共振器の集中定数等価回路図である。
【図6】 実装状態を示すSAW分波器の回路構成図である。
【図7】 Txフィルタの集中定数等価回路である。
【図8】 Rxフィルタの集中定数等価回路である。
【図9】 SAW分波器の基本構成図である。
【符号の説明】
100 ANT端
101 Tx端
102 Rx端
103 PT端
170 アンテナ
180 電力増幅器
190 低雑音増幅器
200 Txフィルタ
210,310 共振器(直列腕S1)
211,311 共振器(直列腕S2)
212,312 共振器(直列腕S3)
220,320 共振器(並列腕P1)
221,321 共振器(並列腕P2)
230 有極用L
300 Rxフィルタ
322 共振器(並列腕P3)
323 共振器(並列腕P4)
400 分波線路
410,510 直列腕SAW共振器S1
520 Rs(抵抗分)[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface acoustic wave duplexer including a band-pass filter having a ladder-type configuration using a surface acoustic wave resonator in a small mobile communication device such as a cellular phone, and is used particularly when applied power is high. The present invention relates to a possible surface acoustic wave duplexer.
[0002]
[Prior art]
In recent years, development of mobile communication equipment terminals such as small and lightweight mobile phones has been rapidly advanced. Along with this, miniaturization and high performance of components used are being pursued. In response to this trend, RF (radio frequency) components using surface acoustic wave (hereinafter referred to as “SAW”) filters have been developed and used. In particular, since the SAW duplexer of FIG. 9 is a device that greatly contributes to the miniaturization of the RF section, it has been actively developed and partially put into practical use.
[0003]
FIG. 9 is a basic configuration diagram of the SAW duplexer. In this figure, a Tx filter (transmission filter) (200) is connected to a Tx end (transmission end) (101) around an ANT (antenna) end (100) to which an antenna is connected, and the Rx end A demultiplexing line (400) and an Rx filter (receiving filter) (300) are connected between the (receiving end) (102).
[0004]
As these SAW devices, in order to improve the performance of mobile communication equipment terminals, a high-performance SAW duplexer with further reduced insertion loss in the pass band and higher attenuation in the attenuation band has been demanded in recent years. As shown in FIG. 9, the SAW branching filter is configured so that the transmission signal and the reception signal do not interfere with each other in order to branch and generate signals in the mobile communication equipment terminal. And a demultiplexing line (400).
[0005]
Each filter and demultiplexing line used here are CDMA (Code Division Multiple Access) systems having general characteristics. In the following, the circuit elements and the like shown in each of the drawings other than FIG. 1 are similarly intended for general characteristics. The data in each table is data based on general characteristics other than the data according to the present invention. The data according to the present invention in the table and the circuit elements of FIG. 1 are those of the AMPS / CDMA system according to the present invention.
[0006]
FIG. 6 is a circuit configuration diagram of the SAW duplexer showing a mounting state.
[0007]
This SAW duplexer amplifies the small signal received at the ANT end (100) to the antenna (170), to the transmit power amplifier (180) that outputs high power at the Tx end (101), and at the Rx end (102) Connected to a low noise amplifier (190).
[0008]
[Problems to be solved by the invention]
Since the transmission filter (200) is applied with high power, the transmission filter (200) needs to be a SAW filter that does not deteriorate characteristics even when the high power is applied. This high power SAW filter is disclosed in, for example, Japanese Patent Laid-Open Nos. 6-29779, 10-303682, and 11-251871.
[0009]
As shown in FIG. 2, the filter used in the above publication is a SAW filter with high power durability by increasing the crossing length and logarithm of SAW resonators constituting the transmission filter and increasing the area per unit current. Is used.
[0010]
FIG. 2 is a circuit configuration diagram of the Tx filter.
[0011]
This Tx filter (200) is configured as a ladder filter composed of series arms S1 (210), S2 (211) and S3 (212), parallel arms P1 (220) and P2 (221), and pole L (230). Has been.
[0012]
However, the SAW filters high power shown in FIG. 2 by using the SAW branching filter of FIG. 9, if you choose to enter a high power, it has been found that the characteristics deteriorate duplexer occurs. Let us look at this characteristic deterioration.
[0013]
In a mobile communication device terminal, the impedance change of the antenna part is inevitably large. Therefore, the performance deterioration of the mobile communication device terminal due to the change in impedance of the antenna unit (170) becomes a problem. In other words, this problem is a technical requirement when the ANT end (100) and the Rx end (102) are terminated at 50 Ω (ohms) when viewed from the duplexer, and the ANT end (100) and the Rx end (102 ), There is a need for technology that does not change in characteristics. However, it is known that when the ANT end (100) and the Rx end (102) are opened, signal disconnection occurs due to characteristic deterioration of the Tx filter (200) or destruction of its series arm.
[0014]
On the other hand, the SAW duplexer shown in FIGS. 9 and 6 in a mobile communication terminal device such as a cellular phone is required to have the following functions in addition to the function of using one antenna for transmission and reception.
[0015]
(1) When the antenna operates normally, that is, when the human impedance of the antenna is 50Ω,
(2) When the antenna is open, that is, when the input impedance of the antenna is infinite,
In each of the cases, a function having no change in characteristics is required.
[0016]
In the case of (1) and (2) above, since the impedance changes suddenly, the fluctuation and destruction of the SAW duplexer characteristics during transmission when power is applied to the SAW duplexer becomes a problem. It is known that the fluctuation and destruction of the SAW duplexer characteristics are mainly caused by deterioration and destruction of the series arm resonator of the transmission filter to which high power is applied.
[0017]
In view of the above problems, an object of the present invention is to reduce the current flowing through the series arm, reduce the applied power of the series arm, and suppress deterioration and destruction of the series arm resonator of the surface acoustic wave filter. .
[0018]
[Means for Solving the Problems]
The present invention employs the following means to achieve the above object.
(1) First series arm surface acoustic wave resonator, second series arm surface acoustic wave resonator, first series arm surface acoustic wave resonator and second series arm surface acoustic wave resonator A plurality of series arm surface acoustic wave resonators connected in series, and the first series arm surface acoustic wave resonator. A plurality of first parallel arm surface acoustic wave resonators connected in parallel to each other and a second parallel arm surface acoustic wave resonator connected in parallel to the third series arm surface acoustic wave resonator. A surface acoustic wave duplexer including a parallel arm surface acoustic wave resonator, wherein the resonance frequency of the third series arm surface acoustic wave resonator is defined as the resonance frequency of the first series arm surface acoustic wave resonator. The resonance frequency of the second series arm surface acoustic wave resonator is different from that of the second series arm surface acoustic wave resonator.
(2) First series arm surface acoustic wave resonator, second series arm surface acoustic wave resonator, first series arm surface acoustic wave resonator and second series arm surface acoustic wave resonator A plurality of series arm surface acoustic wave resonators connected in series to each other and the first series arm surface acoustic wave resonator. A plurality of parallel devices including a first parallel arm surface acoustic wave resonator connected in parallel and a second parallel arm surface acoustic wave resonator connected in parallel to the third series arm surface acoustic wave resonator A surface acoustic wave duplexer including an arm surface acoustic wave resonator, wherein the power applied to the third series arm surface acoustic wave resonator is made different from each other by changing the logarithm or the crossing length . The power applied to the series arm surface acoustic wave resonator and the second series arm surface acoustic wave resonator applied Characterized in that was different from the power.
(3) In the surface acoustic wave duplexer described in (1) above, the resonance frequency of the first series arm surface acoustic wave resonator and the resonance frequency of the second series arm surface acoustic wave resonator are equal. It is characterized by.
(4) In the surface acoustic wave duplexer according to (2), the power applied to the first series arm surface acoustic wave resonator and the power applied to the second series arm surface acoustic wave resonator. Are equal to each other.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0020]
(First embodiment)
FIG. 1 is a circuit diagram of a Tx filter (200) according to a first embodiment of the present invention.
[0021]
In a mobile communication terminal device such as a mobile phone shown in FIG. 6, the output impedance ZPout of the PA terminal (103), which is the output terminal of the power amplifier (180), is normally defined as 50Ω. The output power of the power amplifier (180) is obtained at the Tx end (101) of the SAW duplexer from the relationship between the input impedance ZTin of Tx and the output impedance ZPout of the power amplifier (180) at the Tx end (101) of the SAW duplexer. ) To the Tx filter (200) and the power reflected from the Tx end (101) of the SAW duplexer to the PA end (103) of the power amplifier (180).
[0022]
In a mobile communication terminal device such as a cellular phone, the Tx filter (200) in FIG. 6 includes three serial arms S1 (210), S2 (211), and S3 (212) in FIG. 1 and two parallel arms. Table 1 shows the crossing length and logarithm of a four-stage T-type ladder filter composed of P1 (220) and P2 (221).
[0023]
[Table 1]
FIG. 3 is a circuit configuration diagram of the Rx filter (300). As shown in FIG. 3, the Rx filter (300) includes three serial arms S1 (310), S2 (311) and S3 (312) and four parallel arms P1 (320), P2 (321), P3 ( There are also 6-stage π-type filters composed of 322) and P4 (323), and their crossing lengths and logarithms are shown in Table 2.
[0024]
[Table 2]
FIG. 7 is a lumped constant equivalent circuit diagram of the Tx filter (200).
[0025]
FIG. 8 is a lumped constant equivalent circuit diagram of the Rx filter (300).
[0026]
In FIG. 7, series arms S1 (210) and S3 (212) are circuits in which two unit circuits in which a capacitor CS0 is connected in parallel to a series circuit of reactance LS1 and capacitor CS1 are connected in series, and series arm S2 (211) is a reactance. A series circuit of LS2 and a capacitor CS2 and two unit circuits in which the capacitor CS1 is connected in parallel is connected in series, and the parallel arms P1 and P2 are two unit circuits in which the capacitor CP0 is connected in parallel to the series circuit of the reactance LP1 and the capacitor CP1. The circuit is connected in series.
[0027]
In FIG. 8, series arms S1 (310), S2 (311), and S3 (312) are circuits in which a capacitor CS0 is connected in parallel to a series circuit of reactance LS1 and capacitor CS1, and parallel arms P2, P3, and P4 are connected to reactance LP1. The capacitor CP0 is connected in parallel to the series circuit of the capacitor CP1, and the parallel arm P1 is a circuit in which two unit circuits in which the capacitor CP0 is connected in parallel to the series circuit of the reactance LP1 and the capacitor CP1 are connected in series.
[0028]
Table 1 shows the equivalent LC values of each series arm and parallel arm. The first embodiment of the present invention relates to the configuration of the ladder-type Tx filter (200) of FIG. 1, and in the SAW duplexer of FIG. 6, when transmission power is input, each series arm of the Tx filter (200) of FIG. The power applied to the resonator is reduced.
[0029]
It is necessary to pay attention to the power input to the Tx filter (200) during signal transmission. It can be seen from FIG. 6 that the input power of the Tx filter (200) is related to the input impedance ZTin of the Tx filter (200). That is, at the time of transmission, the load is in a state where the impedance ZRLin of the receiving system including the branch line (400) and the Rx filter (300) is connected in parallel with the ANT end (100).
[0030]
The problem here is that when the power applied to each resonator (210, 211, 212, 220, 221) of FIG. 7 constituting the Tx filter (200) becomes high, the finite Q of each resonator A current flows through the generated intercombination resistance of the resonator, heat is generated in the resonator by this current, and the resonator is destroyed by this heat. However, the resonator “Q”
Q = 2π (accumulated energy) / (energy lost during one cycle)
= 2πf (accumulated energy) / (disappearing power).
[0031]
FIG. 4 is a circuit configuration diagram of the series arm SAW resonator.
[0032]
FIG. 5 is a lumped constant equivalent circuit diagram of the series arm SAW resonator.
[0033]
FIG. 4 is a schematic diagram of the series arm resonator S1 (410), and FIG. 5 is a lumped constant equivalent circuit of the series arm resonator S1 (510) of FIG. 4, and a series circuit of the capacitance Cs1 and reactance Ls1 and the capacitance Cso. Are connected in parallel, and a resistor Rs520 is connected in series to them.
[0034]
Normally, the resistance component due to the finite Q of the series arm resonator S1 (410) of FIG. 4 is evaluated and calculated as the resistance component Rs (520) from the lumped constant circuit of the series arm resonator S1 (510) of FIG. The The resistance component Rs (520) due to the finite Q of the resonator of FIG. 5 is obtained from the lumped constant equivalent circuit of the resonator as follows. Now, assuming that Q of the resonator is finite Q 0 , the impedance Z of the series arm resonator including Q 0 and the admittance Y of the parallel arm resonator are given by Expression (1).
Z = 1 / Y = R d + jZ 0 = 1 / (G d + jY 0) (1)
G d = {ωC 0 + ωC 1 (1 + ω ^ 2 * L 1 * C 1 )} / {(1-ω ^ 2 * L 1 * C 1 ) ^ 2} / Q 0 (2)
Y 0 = ω (C 0 + C 1 + ω 2L 1 * C 1 * C 0 ) / (1 + ω 2 * L 1 * C 1 ) (3)
When the Q of each resonator is infinite, the impedance of the series arm resonator is jZ 0 , and the admittance of the parallel arm resonator is jY 0 . However, since each resonator is actually a finite Q, there exists a minute resistance R d of the series arm resonator and a minute conductance G d of the parallel arm resonator.
[0035]
From the equivalent LC value of each series arm resonator of the Tx filter (200) in Table 1, the resistance value of the Tx filter (200) at 824 (MHz), 836 (MHz) and 849 (MHz) is determined as the Q of each resonator. Table 3 shows values obtained from Equation (1), Equation (2), and Equation (3).
[0036]
[Table 3]
When transmission power is applied to the Tx filter (200), it is divided into equivalent power and reflected power as shown in FIG. This equivalent power is converted into heat by the high frequency resistance of the Tx filter (200) shown in Table 3. Now, in Table 3, when focusing on the frequency 836 (MHz), it can be seen that the resistance value of the series arm 2 is 3.77Ω, which is approximately twice the resistance of 1.93Ω of the
[0037]
[Table 4]
From Table 4, it can be seen that the highest power is applied to the series arm 2. That is, it can be seen that the series arm 2 is the weakest to electric power. This is because the high frequency resistance is large as described above.
[0038]
Usually, the series arms of the Tx filter (200) are set to the same resonance frequency. However, in order to reduce the applied power to the series arm 2, according to Table 3, since the high frequency resistance of each series arm changes when the frequency is changed, the first embodiment of the present invention uses the Tx filter of FIG. By making the resonance frequency of the
[0039]
[Table 5]
In the first embodiment of the present invention, as shown in Table 5, the resonance frequency of the series arm 2 (R3) is set to the high frequency side from 869 (MHz), so that the high frequency resistance of the series arm 2 (R3) is set in this embodiment. According to the example, the power is decreased from 3.77Ω at 869 MHz to 1.93Ω at 885 MHz, and the applied power to the series arm 2 is eventually reduced.
[0040]
Therefore, as means for changing the resonance frequency of the series arm 2 in the first embodiment of the present invention, specifically, means for changing the inter-electrode pitch of the comb electrodes can be adopted. For example, in the case of a grating reflector, assuming that the grating period (metal and dielectric strip arrangement interval) is p and the surface wave velocity is v 0 , the center frequency f 0 of the reflector is an expression of f 0 = v 0 / 2p. Can be obtained from That is, when the surface wave velocity is constant, the resonance frequency of the series arm 2 can be changed by changing the grating period. Furthermore, although the frequency characteristic changes due to the change in the resonance frequency of the series arm 2, this change in frequency characteristic can be corrected by the crossing length and logarithm of each series arm.
[0041]
Table 5 substantially shows the effect of the present invention. Usually, all the serial arms are set to 869 (MHz). Table 5 shows the resistance and applied power in the case of each series arm when the resonance frequency of the series arm 2 is changed to (869 to 885) (MHz). It can be seen that by changing the resonance frequency of the series arm 2 from 869 (MHz) to 885 (MHz), the applied power of the series arm 2 changes from 0.074 (Watt) to 0.019 (Watt).
[0042]
(Second embodiment)
FIG. 2 is a circuit configuration diagram of the Tx filter of the present invention.
[0043]
The circuit configuration of the second embodiment of the present invention is the polar configuration shown in FIG.
[0044]
In the first embodiment, paying attention to the series arm 2 having the largest applied power, the resonance frequency of the series arm 2 is changed, the resistance of the series arm 2 is reduced, and the applied power of the series arm 2 is lowered.
[0045]
On the other hand, in the second embodiment, in the circuit of the Tx filter (200) in FIG. 2, the resistance of the
[0046]
Table 6 shows the resistance values of the parallel arms alone and the resistance values of the serial arms and the parallel arms when the multistage filter is assembled. No. in Table 6 One example is a configuration based on the first embodiment.
[0047]
[Table 6]
An example in which the resistance value of the
[0048]
Table 7 shows the resistance value of the parallel arm alone according to the second embodiment and the power applied to each series arm and parallel arm when the multistage filter is assembled.
[0049]
[Table 7]
No. in Table 7 As described above,
[0050]
As described above, the means for reducing the applied power of each series arm in the circuit configuration of the polarized Tx filter (200) of the second embodiment provides high performance characteristics that cannot be obtained by the configuration of the first embodiment. The first embodiment can be applied at the same time.
[0051]
In the second embodiment, by using a technique in which the high-frequency resistance of the parallel arm is reduced, the current flowing through the series arm is reduced, and the applied power of the series arm is reduced, the power handling characteristics of the polarized Tx filter (200) are improved. Improved.
[0052]
【The invention's effect】
According to the present invention, according to the matters described in the claims, the current flowing through the series arm is reduced, the applied power to the series arm is lowered, and the deterioration and destruction of the series arm resonator of the surface acoustic wave filter can be suppressed. it can.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a Tx filter according to a first embodiment of the present invention.
FIG. 2 is a circuit configuration diagram of a Tx filter.
FIG. 3 is a circuit configuration diagram of an Rx filter.
FIG. 4 is a circuit configuration diagram of a series arm SAW resonator.
FIG. 5 is a lumped constant equivalent circuit diagram of a series arm SAW resonator.
FIG. 6 is a circuit configuration diagram of a SAW duplexer showing a mounted state.
FIG. 7 is a lumped constant equivalent circuit of a Tx filter.
FIG. 8 is a lumped constant equivalent circuit of an Rx filter.
FIG. 9 is a basic configuration diagram of a SAW duplexer.
[Explanation of symbols]
100
211,311 resonator (series arm S2)
212, 312 resonator (series arm S3)
220, 320 resonator (parallel arm P1)
221 and 321 resonator (parallel arm P2)
230 L for polarized
300
323 resonator (parallel arm P4)
400 demultiplexing line 410,510 Series arm SAW resonator S1
520 Rs (resistance)
Claims (4)
前記第3の直列腕弾性表面波共振器の共振周波数を、前記第1の直列腕弾性表面波共振器の共振周波数及び前記第2の直列腕弾性表面波共振器の共振周波数とは異ならせたことを特徴とする弾性表面波分波器。Between the first series arm surface acoustic wave resonator, the second series arm surface acoustic wave resonator, and the first series arm surface acoustic wave resonator and the second series arm surface acoustic wave resonator. A plurality of series arm surface acoustic wave resonators connected in series, and in parallel with the first series arm surface acoustic wave resonator. A plurality of parallel arm elasticity including a first parallel arm surface acoustic wave resonator connected and a second parallel arm surface acoustic wave resonator connected in parallel to the third series arm surface acoustic wave resonator. A surface acoustic wave duplexer including a surface wave resonator,
The resonance frequency of the third series arm surface acoustic wave resonator is different from the resonance frequency of the first series arm surface acoustic wave resonator and the resonance frequency of the second series arm surface acoustic wave resonator. A surface acoustic wave duplexer characterized by that.
対数若しくは交差長を異ならせることによって、前記第3の直列腕弾性表面波共振器に印加される電力を、前記第1の直列腕弾性表面波共振器に印加される電力及び前記第2の直列腕弾性表面波共振器に印加される電力とは異ならせたことを特徴とする弾性表面波分波器。Between the first series arm surface acoustic wave resonator, the second series arm surface acoustic wave resonator, and the first series arm surface acoustic wave resonator and the second series arm surface acoustic wave resonator. A plurality of series arm surface acoustic wave resonators connected in series, and connected in parallel to the first series arm surface acoustic wave resonator. A plurality of parallel arm surface acoustic wave surfaces including a first parallel arm surface acoustic wave resonator and a second parallel arm surface acoustic wave resonator connected in parallel to the third series arm surface acoustic wave resonator A surface acoustic wave duplexer including a wave resonator,
By making the logarithm or crossing length different, the power applied to the third series arm surface acoustic wave resonator is changed to the power applied to the first series arm surface acoustic wave resonator and the second series arm surface acoustic wave resonator. A surface acoustic wave duplexer characterized in that it is different from the power applied to the arm surface acoustic wave resonator.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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JP2001328692A JP3980323B2 (en) | 2001-10-26 | 2001-10-26 | Surface acoustic wave duplexer |
US10/273,887 US6911878B2 (en) | 2001-10-26 | 2002-10-21 | Acoustic wave branching filter having transmitting filter with optimal power handling |
US10/983,788 US7420440B2 (en) | 2001-10-26 | 2004-11-09 | Transmitting filter including SAW resonators |
Applications Claiming Priority (1)
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JP2001328692A JP3980323B2 (en) | 2001-10-26 | 2001-10-26 | Surface acoustic wave duplexer |
Related Child Applications (1)
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JP2007075102A Division JP2007209024A (en) | 2007-03-22 | 2007-03-22 | Surface acoustic wave filter |
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JP2003133902A JP2003133902A (en) | 2003-05-09 |
JP3980323B2 true JP3980323B2 (en) | 2007-09-26 |
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JP2001328692A Expired - Fee Related JP3980323B2 (en) | 2001-10-26 | 2001-10-26 | Surface acoustic wave duplexer |
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JP (1) | JP3980323B2 (en) |
Cited By (1)
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JP2007209024A (en) * | 2007-03-22 | 2007-08-16 | Oki Electric Ind Co Ltd | Surface acoustic wave filter |
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JP3980323B2 (en) * | 2001-10-26 | 2007-09-26 | 沖電気工業株式会社 | Surface acoustic wave duplexer |
JP2005045475A (en) | 2003-07-28 | 2005-02-17 | Murata Mfg Co Ltd | Surface acoustic wave device and communications apparatus |
US8476991B2 (en) | 2007-11-06 | 2013-07-02 | Panasonic Corporation | Elastic wave resonator, elastic wave filter, and antenna sharing device using the same |
WO2009060594A1 (en) * | 2007-11-06 | 2009-05-14 | Panasonic Corporation | Elastic wave resonator, elastic wave filter, and antenna sharing device using the same |
Family Cites Families (18)
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JP3194540B2 (en) | 1992-07-13 | 2001-07-30 | 富士通株式会社 | Surface acoustic wave filter |
DE69412424T2 (en) * | 1993-11-05 | 1998-12-24 | Matsushita Electric Ind Co Ltd | Acoustic surface wave filter |
US5471178A (en) * | 1994-02-03 | 1995-11-28 | Motorola, Inc. | Ladder filter and method for producing conjugately matched impedance |
US5786738A (en) * | 1995-05-31 | 1998-07-28 | Fujitsu Limited | Surface acoustic wave filter duplexer comprising a multi-layer package and phase matching patterns |
JP3243976B2 (en) * | 1995-08-14 | 2002-01-07 | 株式会社村田製作所 | Surface acoustic wave filter |
JPH10200370A (en) * | 1997-01-10 | 1998-07-31 | Murata Mfg Co Ltd | Surface acoustic wave filter |
EP1326333B1 (en) * | 1997-02-12 | 2008-08-20 | Oki Electric Industry Co., Ltd. | Surface-acoustic-wave filters with poles of attenuation created by impedance circuits |
JPH10303682A (en) | 1997-04-23 | 1998-11-13 | Oki Electric Ind Co Ltd | Surface acoustic wave resonator and resonator type surface acoustic wave filter |
JP3241293B2 (en) * | 1997-04-25 | 2001-12-25 | 富士通株式会社 | Surface acoustic wave device and duplexer using the same |
US5949306A (en) * | 1997-12-02 | 1999-09-07 | Cts Corporation | Saw ladder filter with split resonators and method of providing same |
JPH11251871A (en) * | 1998-03-06 | 1999-09-17 | Oki Electric Ind Co Ltd | Receiving filter of surface acoustic wave branching filter |
JP3228223B2 (en) * | 1998-05-26 | 2001-11-12 | 株式会社村田製作所 | Surface acoustic wave filter |
JP2000286676A (en) * | 1999-03-31 | 2000-10-13 | Sanyo Electric Co Ltd | Surface acoustic wave filter |
JP3403669B2 (en) * | 1999-06-04 | 2003-05-06 | 富士通株式会社 | Antenna duplexer |
JP3449352B2 (en) * | 2000-02-07 | 2003-09-22 | 株式会社村田製作所 | Surface acoustic wave filter |
JP4352572B2 (en) * | 2000-04-03 | 2009-10-28 | パナソニック株式会社 | Antenna duplexer |
JP3363870B2 (en) * | 2000-05-29 | 2003-01-08 | 沖電気工業株式会社 | Surface acoustic wave duplexer |
JP3980323B2 (en) * | 2001-10-26 | 2007-09-26 | 沖電気工業株式会社 | Surface acoustic wave duplexer |
-
2001
- 2001-10-26 JP JP2001328692A patent/JP3980323B2/en not_active Expired - Fee Related
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2002
- 2002-10-21 US US10/273,887 patent/US6911878B2/en not_active Expired - Lifetime
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2007209024A (en) * | 2007-03-22 | 2007-08-16 | Oki Electric Ind Co Ltd | Surface acoustic wave filter |
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Publication number | Publication date |
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US20050134407A1 (en) | 2005-06-23 |
JP2003133902A (en) | 2003-05-09 |
US7420440B2 (en) | 2008-09-02 |
US6911878B2 (en) | 2005-06-28 |
US20030117233A1 (en) | 2003-06-26 |
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